Soybean is used in a great quantity as an industrial material for soybean oil, defatted soybean and soybean protein. In addition, an enormous quantity of soybean has been used since ancient times as a material for cooked bean, "KINAKO"--a baked soybean four, fermented soybean, "MISO"--a soybean paste, soy sauce, soybean milk, soybean curd, dried soybean curd, "KOYA-TOFU", "ABURAGE", or "HIRYOZU".
Soybean is a very suitable material for health foods because it contains, in addition to substantial amounts of vitamin E and lecithin, large amounts of protein and fat which are riched sources for essential amino acids or fatty acids.
It is well documented that soybean contains biologically-active glycosides. For example, as reported in Chem. Pharm. Bull., Vol. 24, No. 1, pp. 121-129 (1976), or Up-to-Date Foodprocessing, Vol. 17, No. 9, pp. 39-47 (1982), soybean contains a substantial amount of soyasaponin bearing a soyasapogenol moiety as aglycon. Furthermore, as described in Up-to-Date Foodprocessing, Vol. 16, No. 5, pp. 36-40 (1981) or ibid., Vol. 17, No. 7, pp. 30-42 (1982), it has been well documented that soyasaponin exhibits biological activities, such as hypolipidemic and hypocholesterolemic effects. Also, as reported in Chem. Pharm. Bull., Vol. 24, No. 1, pp. 121-129 (1976), Up-to-Date Foodprocessing, Vol. 17, No. 7, pp. 30-42 (1982), or ibid., Vol. 17, No. 9, pp. 39-47 (1982), soybean contains substantial amounts of isoflavonoids, such as genistin, acetylgenistin, daidzin, acetyldaidzin, and glycitein 7-O-beta-glucoside. Furthermore, as described in Up-to-Date Foodprocessing, Vol. 17, No. 7, pp. 30-42 (1982), it has been well documented that isoflavonoids exhibit biological activities, such as hypolipidemic, hypocholesterolemic and antihaemolytic activities.
Accordingly, ingestion of soybean foods facilitates the uptakes of soybean glycosides, such as soyasaponin or isoflavonoid, as well as uptakes of the above described essential amino acids, essential lipids, vitamin E and lecithin. Thus, it is clear that soybean foods are much superior other health foods.
Recently, food products wherein such soybean glycosides are incorporated or soybean foods containing the same are available as dietary foods and drinks, or foods and drinks directed for promoting or retaining beauty or health. It is known that these food products, however, have a disadvantage of causing, in addition to bitter, astringent and harsh tastes, a lingering choky taste, for which the soybean glycosides are responsible.